Field of the Invention
The present invention relates to a folding and glueing device for folding and applying glue to the closure flaps of blanks in continuously moving "wrap-around" sleeve packaging devices, as disclosed, for instance, in British Patent Specification 2 233 954 in the name of the applicants.
The invention relates more particularly to a folding and glueing device of the above-mentioned type that is particularly adapted to cardboard wrap-around packagings in which the closure flap is articulated on the free end of the rear panel and has to be disposed within the finished package.
In this particular technological sector, the wrap-around blanks used by these packaging machines substantially comprise a first set of panels, normally four, extending longitudinally and consecutively in order to form the rear wall, the base wall, the front wall and the upper wall of the package when it is wound in the form of a sleeve about the product, eight lateral flaps articulated on the opposite longitudinal sides of the four panels mentioned above and adapted to form the heads of the package and a closure flap articulated on the longitudinal free end of the rear panel and adapted to be glued underneath the longitudinal free end of the upper panel.
Continuous packaging machines of the wrap-around sleeve type comprise a production line that substantially carries out the following operations: the association of the individual products with respective individual blanks by disposing these products on the base panel of these blanks; the partial winding of the individual blanks in the form of a sleeve about the respective products by erecting the rear panel against the rear portion of the product, the front panel against the front portion of the product and the upper panel over the upper portion of the product in a partly raised manner; the folding back over the heads of this product of the four flaps articulated on the sides of the rear panel and on the sides of the front panel; the folding towards the interior of the package of the closure flap and the application of glue to the upper surface thereof; the lowering of the upper panel in order to cause this closure flap to adhere to the inner longitudinal end portion of the upper panel; the application of glue to the outer surfaces of the four flaps previously folded back over the heads of the product; and, lastly, the folding of the flaps articulated on the upper panel and on the base panel against the flaps previously folded against the heads in order to obtain the fastening of these flaps.
At present, operations to fold the closure flap towards the interior of the package and to apply the glue thereto are carried out by folding and glueing devices provided with an alternating and/or intermittent movement which do not enable faultless folding of the closure flap, do not enable the use of high operating speeds and do not enable the correct application of the glue since during the spraying of this glue the plane of the closure flap is not perpendicularly opposite to the direction of spray from the nozzles.